[klaudius]

  "If Bill Gates had been born and raised in Ruanda, you wouldn't know his name today."

You are unfairly using an extreme example. It would be like saying that someone wouldn't be 6'5" if they had been born in extreme poverty with malnutrition. Yes, extremely bad environment can stunt your growth, but you can't use poverty and malnutrition to explain in general why some people are shorter or taller than others.

There are wealthy people outside of the USA and those who weren't born wealthy.

It's a mistake to claim that differences in wealth (or height or IQ) can be explained by environmental factors.